Azo dyes from condensation products of p-aminosalicylic acid



United States Patent AZO DYES FROM CONDENSATION PRODUCTS OFP-AMINOSALICYLIC ACID Hans Z. Lecher, Plainfield, and Bennett G. Buell,Somerville, N. 1., assignors to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Original application June 16,1953, Serial No. 362,146. Divided andv this application February 14,1956, Serial No. 565,319

7 plaims. (Cl. 260-144) This invention relates to new couplingcomponents of the formula in which X is hydrogen or acyl and COY is acarboxylic acid or carboxarylide group and n is an integer -l.

Brown is a difiicult shade to produce in azo dyes. When browns areformed, they are usually deficient tinctorially or in fastnessproperties. Thus, browns may be formed by coupling diazonium salts intoarylides of paminosalicylic'acid, but they are weak in color .value andarenot satisfactory in fastnessvalue's'. .There is a great need in theazo field for a good strong fast brown to fill out the range of colorsavailable. 7

v The new coupling components of the present invention can be used toproduce browns of good properties. It is an advantage of the presentinvention that the new coupling components couple easily with the usualaromatic diazo compounds, producing shades which are stronger in colorand better in fastnes s than those-obtainable from p-aminosalicylic aciditself and its arylides. The number of diazo groups can be Varied fromas little as 1 group per coupling component molecule to as many as arerepresented by the number of rings in the coupling component. In otherwords, "the number of azo groups can vary from 1 to n+2 depending on theparticular coupling component. The shade 'of course varies with theproportions of the diazo compounds and hence with the mb ia r u sjn rmol ul r The new coupling componentscan be: considered as condensationpolymers of p-aminosalicylic'acid with or without additional groupsattached .to the terminal NH and to the terminal COOH group asrepresented by X and Y in the formula given above. Various methods maybe'used to produce the compounds. One good method is to heat themonomer, p-aminosalicylic acid, in an organic solvent with thionylchloride. The thionyl chloride forms the acid chloride ofp-aminosalicylic acid which condenses with more p-aminosalicylic acid insitu. 'We have found that the extent of condensation obtained by thisprocess depends on the solvent. In solvents which are not good acidbinding agents, such as, for example, dioxane, the product has anaverage molecular weight corresponding to a mixture of trimer ortetramer. However, when a tertiary base such 'as' pyridine, picoline,dimethylaniline, quinoline and the like is used as a solvent, and thusmaintains in the reaction mixture a good acid binding agent, thecondensation goes further, producing an average molecular weight ofproduct corresponding to the condensation of from 5 to 6 monomers.

.When the condensation products are prepared by the above describedmethods, they have a terminal amino and a terminal carboxy group. Insuch a form they are useful as coupling components. If preferred,however,

one or both of the terminal groups may be blocked by reaction withsuitable reagents. For example, the carboxy groups can be reacted witharomatic amines such as aniline, p-chloroaniliue, o-phenetidine,Z-methoxy-S-bromoaniline, 2-ethoxy-5-chloroaniline, p-anisidine,p-toluidine, o-toluidine, dianisidine, 2,5-dimethoxyaniline,alphanaphthylamine, m-nitraniline,-and the like to form arylides. Theamino group at the other end of the polymer can also be tied up byacylation using, for example, acetic anhydride, benzoyl chloride orderivatives thereof.

In addition to the direct polymerization, polymers can be prepared bycondensing an N-acyl-p-aminosalicylic acid chloride with an arylide ofp-aminosalicylic acid. By careful deacylation of the product, the freeaminosalicyloylaminosalicylarylide is formed, which can be made into atrimer by further reaction with an acyl-p-aminosalicylic acid chloride.The condensation product can thus be built up stepwise.

The coupling components prepared by either method and with or withoutthe blocking of one or both of the terminal NH and carboxy groups, canbe used to form azo dyes by the various methods in which azo dyes arenormally produced. Thus for example, the dyes can be and then over.printing or immersing in a solution of the diazo compound desired, orthe diazo compound may be converted into a diazoamino or other compoundwhich does not couple in alkaline solution, incorporated into analkaline printing paste containingthe coupling component and printed,and the color developed on the'fiber by conventional methods such asacid aging. If suflicient diazo compound is present, more than one diazowill couple on each molecule of the coupling component.

It is an advantage of the present invention that the couplingcomponentsmay be used with;any of the wellknown and conventional diazo components.Thus, forexarnple, there may be used diazo components such asdianisidine, benzidine, 4-nitro-2-methoxyaniline,.5-nitro 2-methoxyaniline, 2-nitro-4-methoxyaniline,- 2,5-dichloroaniline,4-benzamido 2 methoxy 5 methylaniline, 2- methyl 4-chloroaniline,2-methyl-S-chloroaniline, 4-benzamide-2,5-dimethoxy (anddiethoxy)-aniline, Z-methoxy- 5-chloroaniline, 2-nitro-4-methylaniline,2-methyl-4-nitroaniline, 3-amino-4-methoxybenzene sulfondiethylamide,4-amino diphenylamine, 4-amino-4'-methoxy diphenylamine,alpha-aminoanthraquinone, and the like.

As has been pointed out above, the formation of dyed materials can beeflected by any of the conventional methods of dyeing or printing withazo dyes. In some of the cases the diazo compound is applied in a formin which coupling takes place directly. In others, the diazo compound isstabilized against azoic coupling under alkaline conditions and isapplied in the form of a paste or an alkaline dye bath and is thendeveloped by setting free the diazo compound by means of acid vapors orother conventional methods. In each case the actual formation of the azodyes involves a reaction of a diazo cornpound with the new couplingcomponent and so'when in the claims this reaction is referred to, itshould be understood that it is intended to include any of the abovecases regardless of whether the 'diazo compound is first added as suchor is developed by acid aging or other methods.

The invention will be illustrated in greater detail in the followingspecific examples in which the parts are by weight unless otherwisespecified.

Example 1 A mixture of 153 parts of 4-aminosalicylic .acid and 1,000parts of dioxane is stirred at 71-75" C. while 144 parts of thionylchloride is added gradually. The mixture is then stirred at 6570 C. forsome time and then'cooled 3 to room temperature. The light yellow solidis filtered, washed and dried. Thi crude product is freed of monomer byslurrying in 1,000 parts of water and 300 parts of saturated sodiumacetate solution, filtering, and washing with water and alcohol. It is alight yellow solid, insoluble in common organic solvents, water, orsodium bicarbonate solution. It dissolves in caustic soda solution.Nitrite titration shows the average molecular weight to be about 480.There are no additional groups attached to the terminal NH and COOHgroups. The dyeings with the above compound show good fastnessproperties.

Example 2 A mixture of 15.3 parts of 4-aminosalicylic acid in 100 partsof pyridine is stirred at SIS-60 C. While 16.3 parts of thionyl chlorideis added gradually. The mixture is then stirred at 55-60 C. for sometime, and finally cooled. It is then drowned in 500 parts of water, andthe drowned mixture is neutralized with sodium bicarbonate. The pyridineis removed with steam, and the residual liquor is acidified with aceticacid. The gelatinous product is isolated by filtration and dried invacuo over caustic potash. It has the same characteristics as theproduct of Example 1 except that its average molecular weight is about700. The dyeings with the above compound show good fastness properties.

Example 3 Two parts of the product of Example 1 is dissolved in 60 partsof water and 0.54 part of sodium hydroxide. Two parts ofo-chlorobenzoylchloride is added, and the mixture is stirred a shorttime at room temperature. Carbon dioxide gas is then passed through toneutralize the caustic and the light-colored product is isolated byfiltration. It is purified by extraction with dilute hydrochloric acidand dilute sodium bicarbonate. It is insoluble in organic solvents anddissolves very slowly in caustic soda. The dyeings with the abovecompound show good fastness properties.

Example 4 A mixture of 6 parts of the product of Example 1, 6.35 partsof p-chloroaniline, 40 parts of toluene, and 1.57 parts of phosphorustrichloride is stirred at reflux until the reaction is substantiallycomplete. The mixture cooled, and the product is isolated by filtration.It is purified after drying by alkaline extraction with sodium carbonatesolution and then acid extraction with dilute rydrochlon'de acid. Thedyeings with the above compound show good fastness properties.

Example 5 CHaCONH OH O O-NH OH 01 C ONE A mixture of 39 parts of4-acetaminosalicylic acid, 50 parts of 4'-chloro-4-aminosalicylanilideand 440 parts of toluene is stirred at 90 C. while 15.4 parts ofphosphorus trichloride is added gradually. The mixture is refluxed untilthe reaction is substantially complete, and then cooled. The product isisolated by filtration and after drying, is freed of by-products byrepeated extraction with aqueous sodium bicarbonate. It is finallyprecipitated with acid from a caustic soda solution. The product is alight-colored solid which does not melt below 325 C. and is insoluble inmost organic solvents except pyridine. It can be recrystallized from apyridine-alcohol mixture to give a white solid with the correctanalysis. Dyeings with the abovecompound show good fastness.

Example 6 The product of Example 1 was incorporated in a standardprinting formulation, in a concentration of 1%, and printed on cottoncloth. The cloth was then treated with 4 various diazotized aromaticamines to permit coupling on the fiber. The products had the followingshades:

f dy Dianisidine Red brown. 4-chloro-2-nitroaniline Yellow brown.l-aminoanthraquinone Brown. 4-methoxy-2-nitroaniline-- Olive brown.m-Chloroaniline Red brown. 2,5-dichloroaniline Olive brown.2-methoxy-4-nitroaniline Red brown.

The dyeings with the above compound show good fastness properties.

Example 7 Printing pastes of the following compositions were compoundedand used to print cotton cloth. The printings, after acid aging, gavethe indicated colors:

CHs TnHa A--." O N N=NN 49.6 parts.

NaO O C S osNa Product of Example 1 17.6 parts Sodium Aluminate 2 parts.Sodium sulfate 3.2 parts.

Color bright red brown. CH3 CH3 EH B (M10 0 O--OHN-N=N 54.4 parts.

Product of Example 1 31.2 parts. Sodium alumlnate 1 4.0 parts. sodiumsulfate 96.8 parts. Color red brown.

CH; (32 0--." OzN-O-.N=NN 51.9 parts.

N a0 0 C S OaNa Product of Example 2 16.9 parts. Sodiumaluminate 2.0parts. Sodium lf 0.6 parts. Color brown.

32 5 D..... O:N N=NN 40.9 parts.

NaO 0 C BOaNa Product of Example 5 21.9 parts. Sodium aluminate..- 2.0parts. Sodium sulfate 12.4 parts. Color p light yellow Os; /CH O CHbrown I E (N210 0 C..CH:..N.=NI l, 13.6 parts Product of Example 3Sodium alumlnate Sodium sulfate tion Serial No. 362,146, filed June 16,1953.

We claim: 1. A20 dyes obtained by coupling a compound of the andcarboxylic acyl, Y is chosen from the group consiststructure ing of OHand --NH--Ar in which Ar is an aryl radical and n is an integer 1 with adiazo compound.

It-NH OH OH H- OH 5 2. A20 dyes according to claim 1 in which n is aninteger -1 7 and the carboxylic acyl group does not i C C .00! 1 containmore than 1 carbocyclic ring.

' n I 3. A20 dye mixtures having the structure in which X is selectedfrom the group consisting of H j 0H NH 08 CO 00 OH in which n has anaverage value of one. 4. Azo dye mixtures of the formula in which n hasan average value of one.

5. A20 dye mixtures of the formula cm 1 NE on 1? ONO-mm c m: on a n a aa o oooa in which n has an average value of three.

6. A20 dye mixtures of the formula on NE on NE on 01 co co 0 co-ua inwhich n has an average value of one.

7. A20 dye mixtures of the Eormula in which n has an average value ofone.

References Cited in the file of this} patent UNITED STATES PATENTS2,047,515 Laska et a1; July 14, 1936 FOREIGN PATENTS 10,168 GreatBritain Oct. so, 1913

1. AZO DYES OBTAINED BY COUPLING A COMPOUND OF THE STRUCTURE